The present application claims priority under 35 U.S.C. xc2xa7119 of German Patent Application No. 100 19 568.7, filed on Apr. 20, 2000, the disclosure of which is expressly incorporated by reference herein in its entirety.
1. Field of the Invention
The invention relates to a measuring system for determining properties of a running paper, cardboard, tissue, or other fibrous material web, in particular arranged in the drying section of a machine for the production and/or finishing thereof, in which the fibrous material web partially wraps at least one upper and one lower roll and an angle of 0 to 45xc2x0 to a vertical runs between these rolls, with at least one sensor for detecting a web property being arranged in the region of the lower roll on a sensor guide traversing the fibrous material web in a crosswise manner.
2. Discussion of Background Information
In order to optimize the production and/or finishing process, it is constantly becoming more important to detect the operating condition of the running fibrous material web. These values can then be used, for example, in controls for the purpose of profiling.
Because of the high speeds, supporting the fibrous material web in these machines with a belt or a roll is indispensable, which makes measurement even more difficult with respect to accessibility and accuracy.
Furthermore, in stationary measuring systems, considerable problems result from the soiling of the sensor and the sensor guide. Added to this is the difficult accessibility for cleaning and maintenance.
The present invention decreases the soiling of the stationary measuring system and improves the accessibility of the measuring system to the greatest extent possible.
According to the invention, the sensor is arranged in a position in which it forms an angle with a maximum value of about 60xc2x0 with a horizontal with respect to the axis of the lower roll.
These positions lie in the region of the fibrous material web, which is running more or less vertically upwards or downwards. In this region, soiling can be best prevented because web residuals, or similar parts that have been entrained, fall through the gap between the sensor and the fibrous material web into the machine cellar. If the sensor is attached below the axis of the lower roll, it is advantageous for the sensor to form an angle with a maximum value of about 30xc2x0 with a horizontal with respect to the axis of the lower roll. If the sensors are arranged above the axis of the lower roll, the angle with the horizontal is limited by the minimum distance from the fibrous material web. In the instant invention, the fibrous material web is supported by the lower roll during measurement or is running between the upper and lower rolls.
The same advantages with respect to soiling occur when the sensor guide also runs in a position above or below the axis of the lower roll in that it forms an angle with a maximum value of about 60xc2x0 with the horizontal with respect to the axis of the lower roll. In the case of sensor guides that are positioned below the axis of the lower roll, it is also advantageous for the sensor guide to form an angle with a maximum value of about 30xc2x0 to the horizontal with respect to the axis of the lower roll.
The sensor and/or the sensor guide can also be arranged at the height of the lower roll.
The positions of the sensor and sensor guide are naturally to be regarded in connection with one another, the sensor should be allowed the best possible protection from soiling in the interests of measuring accuracy. Here, the placement of the sensors in the sensor guide could also be advantageous.
Depending on the requirements, the sensor guide can incorporate several sensors or several sensor guides can be present for each one or more sensor(s).
It is generally important for the measuring results for the sensors to maintain a constant distance from the fibrous material web during traversing. One basis for this is the support of the fibrous material web, preferably along with a belt on the lower roll. This belt can guide the fibrous material web between the upper and the lower roll, with the fibrous material web being directly in contact with the upper roll.
For reasons of safety of the device and in order to guarantee a sufficiently large space for impurities to drop into the machine cellar, the sensor should be arranged at a distance from the fibrous material web, preferably from the lower roll as well, of between about 3 and 50 cm, in particular between about 8 and 25 cm.
It is further advantageous here for the sensor preferably to be arranged together with the sensor guide on the web exit side of the lower roll. This simplifies the insertion of the fibrous material web and the transfer of a strip of it and reduces the danger of soiling.
Nevertheless, the sensor and the sensor guide should be protected from soiling by deflecting plates or the like. Furthermore, it is advantageous for the sensor guide to be structured in such a way that it allows a movement of the sensor across the width of the fibrous material web at least on one side of the machine, preferably past the rolls. This makes it possible for the sensor to be moved into the areas of the fibrous material web in danger of soiling only for measuring. The ability of the sensor to be moved past the rolls allows its maintenance and cleaning even while the machine is in operation.
In order to guarantee a stable sensor guide as well as a simple construction, the sensor guide should be connected on at least one side of the machine to its seating or foundation.
Depending on the type of control or regulation as well as on the place of measurement in the machine, the sensor can detect the temperature and/or the moisture and/or a tear of the fibrous material web. Because of the significance of these measuring results for influencing the moisture cross profile, the use of the measuring system in a drying section of a paper machine is particularly advantageous. For this purpose, the upper roll should be embodied as a heated drying cylinder and/or the lower roll as a suctioned guide roll and/or the belt as a drying wire. However, depending on the type of drying section, the lower roll can also be formed by a normal roll (guide or drying roll).
It is also possible to use this measuring system in the pressing section for dewatering the fibrous material web or between the pressing section and the drying section. Here, the belt can be embodied as a pressing felt, transfer belt, or a drying wire.
The present invention is directed to a measuring system for determining properties of a running fibrous material web in a drying section of a machine for producing or finishing the fibrous material web. The system comprises at least one upper roll and at least one lower roll. The fibrous material web is arranged to partially wrap at least one upper roll and at least one lower roll and to run between at least one upper roll and at least one lower roll at an angle between about 0 and 45xc2x0 to a vertical. A sensor guide is arranged crosswise to a web run direction, and at least one sensor is arranged to traverse the sensor guide in the web run direction in a region of at least one lower roll. At least one sensor is structured and arranged for determining a web parameter, and at least one sensor is oriented to form a maximum angle of about 60xc2x0 to a horizontal through an axis of at least one lower roll.
In accordance with a feature of the instant invention, the fibrous material web can be one of paper, cardboard, or tissue.
In accordance with another feature of the invention, the at least one sensor can be positioned below the axis of the at least one lower roll and can be oriented to form a maximum angle of about 30xc2x0 to the horizontal through the axis of the at least one lower roll.
According to still another feature of the invention, at least one sensor may be arranged above the axis of at least one lower roll.
Further, the at least one sensor guide may be arranged to form a maximum angle of about 60xc2x0 to the horizontal through the axis of at least one lower roll. At least one sensor guide may be located below the axis of at least one lower roll and can be arranged to form a maximum angle of about 30xc2x0 to the horizontal through the axis of at least one lower roll. Still further, at least one sensor guide can be located above the axis of at least one lower roll.
According to a further feature of the invention, at least one sensor may be arranged on a web exit side of at least one lower roll.
At least one sensor can be arranged, along with the sensor guide, on a web exit side of at least one lower roll.
Moreover, the sensor guide can be structured to facilitate movement of at least one sensor over a width of the fibrous material web at least on one side of the machine. The sensor guide can be structured to facilitate movement of at least one sensor over a width of the fibrous material web and beyond a width of at least one upper and lower rolls.
In accordance with a still further feature of the present invention, at least one sensor guide can be coupled to at least one of a seating and a foundation of the machine at least on one side of the machine.
At least one sensor may be located a distance from the fibrous material web of between about 3 and 50 cm. Further, at least one sensor can be located a distance from the material web of between about 8 and 25 cm.
At least one sensor may be located a distance from at least one lower roll of between about 3 and 50 cm. Further, at least one sensor can be located a distance from at least one lower roll of between about 8 and 25 cm.
According to another feature of the invention, at least one sensor may be arranged to detect at least one of a temperature and a moisture of the fibrous material web.
In accordance with still another feature of the instant invention, at least one upper roll may include a heated drying cylinder.
In accordance with another feature of the invention, at least one lower roll can include a suctioned guide roll.
According to still another feature of the present invention, a belt can be arranged to guide the fibrous material web through the machine. The belt may include a drying wire.
In accordance with yet another feature of the instant invention, a doctor can be arranged against the surface of at least one upper roll, and at least one sensor may be arranged so that materials removed by the doctor do not soil the sensor(s).
The present invention is directed to a process for determining properties of a running fibrous material web in a drying section of a machine for producing or finishing the fibrous material web, which includes at least one upper roll, at least one lower roll, a sensor guide and at least one sensor. The process includes guiding the fibrous material web to partially wrap at least one upper roll and at least one lower roll. The fibrous material web is also arranged to run between at least one upper roll and at least one lower roll at an angle between about 0 and 45xc2x0 to a vertical. The process also includes moving at least one sensor, which is oriented to form a maximum angle of about 60xc2x0 to a horizontal through an axis of at least one lower roll, to a web run direction in a region of at least one lower roll, where at least one sensor is structured and arranged for determining a web parameter.
Other exemplary embodiments and advantages of the present invention may be ascertained by reviewing the present disclosure and the accompanying drawing.